"It's called research chemicals, and everyone out there in the festival is the guinea pig." -- Jarod Brignac, 24

The best friends had traveled together to music festivals all over the country. Sometimes, they would take drugs. But they had one rule: Never accept drugs from strangers.

Clayton Otwell, 21Family photo

But on Saturday, after a night drinking vodka-Red Bulls at Voodoo Festival at City Park, 21-year-old Clayton Otwell, of Little Rock, Ark., apparently forgot his rule, said Mandie Newell, his best friend and companion at the festival.

A stranger, wanting to repay Otwell for helping find his cell phone, offered Otwell a free dose of 25-I, a new synthetic hallucinogenic drug. As Newell watched, her friend knelt and the stranger plopped a single drop from a vial into Otwell's nose.

Otwell immediately started babbling incoherently, Newell said. She got him to the medical tent at the festival, but within 30 minutes, he had a seizure and never regained consciousness. Taken to Tulane University Hospital, he was placed on life support Saturday night; he died Tuesday.

"I honestly don't know why he took it," Newell said a few days after Otwell's death. "I guess the drinking impaired his judgment on whether or not he should take it. I think he just felt really good for helping the kid find his phone and he trusted him."

Otwell was one of at least three people treated for 25-I overdoses during Voodoo Festival weekend, one local emergency room doctor said, noting that friends of all three had indicated it was their first time taking the drug.

Otwell's friends said dealers at Voodoo Fest had been offering people doses of 25-I all weekend, marketing it as artificial LSD or artificial mescaline. "This weekend, it was everywhere," said Jarod Brignac, 24, who also was with Otwell at the festival. "The people had bottles and bottles of it; they were walking through the crowd, trying to make a dime off people at the festival."

The drug, sometimes called "N-Bomb" for its chemical composition 25I-NBOMe, is an extremely potent synthetic substance that the Drug Enforcement Administration considers analogous to LSD and therefore illegal in all 50 states, said DEA Special Agent Bob Bell.

Around 2009, Bell said, many academic research papers were published regarding the pharmacological effects of synthetic compounds. Since then, those so-called "research drugs" have proliferated in the United States, Bell said, in part because of a widespread misconception that they are safe and legal. He said that for the most part, the drugs are coming in from other countries, but are sometimes made in home labs in the U.S. Synthetic drugs have grown popular especially among people who have to pass regular drug screenings, including athletes and soldiers, because the drugs are not detectable on current drug screens, DEA officials said.

"They're purported as legal and safe, but they're anything but, and in many instances, they're more dangerous than any of the illicit drugs we're all used to," Bell said.

It's hard to pinpoint when 25-I first appeared on the scene, but 2012 has seen an uptick in 25-I-related overdoses and deaths, Bell said. Two teenagers in Grand Forks, N.D. and a 16-year-old boy in Sacramento, Calif., are believed to have died from 25-I overdoses earlier this year, DEA officials said.

Until this past weekend's Voodoo Festival, however, one New Orleans emergency room doctor said he had never heard of the drug. One of the overdose patients had a vial labeled "25-I" that doctors were able to research so they could have a better idea of how to try and treat that patient, a doctor said.

"They have a seizure, lose consciousness," said Dr. Joseph Lasky, a Tulane emergency room doctor. "Long-term effects range from death on one extreme, to, well -- as far as fully recover, I don't know."

The potency of the drug is intense from the onset, said Brignac, who said he has taken 25-I once. "It disorients you very, very quickly," he said. "Within 20 minutes, the lights from a stage at the other side of the festival are fully starting to take over your vision. It's very, very strong to the point of not wanting to move and you start panicking."

At Voodoo and other music festivals, Brignac said, drug dealers do not warn people about the drug's possible effects. "It's called research chemicals, and everyone out there in the festival is the guinea pig," Brignac said. "How human beings can do it to one another is beyond me."

Meanwhile, Otwell's mother, Dayna Duncan, said she hopes others will learn from her son's death. Parents should "warn their kids about this drug since it's so new and no one knows about it, so we can save lives," the grieving mother said.

As for the stranger who gave her son the fatal drop of 25-I, an overwhelmed Duncan said she hoped eventually justice would be served.

"I think he needs to be exposed," she said, "and held accountable for his actions."